Anastomosis device having at least one frangible member

ABSTRACT

An anastomosis device may include at least one first element connectible to at least one second element, where at least one first element is frangible. At least one second element may include at least one opening therethrough, where each opening receives a corresponding first element. At least one deflectable tab may extend into at least one opening to engage a corresponding first element.

This application is a continuation of U.S. patent application Ser. No.10/197,352, filed on Jul. 16, 2002, now U.S. Pat. No. 6,805,708 which inturn is a continuation of U.S. patent application Ser. No. 09/778,003,filed Feb. 7, 2001, now U.S. Pat. No. 6,497,710, issued on Dec. 24,2002, which in turn is a divisional of U.S. patent application Ser. No.09/133,185, filed Aug. 12, 1998, now U.S. Pat. No. 6,206,913, issued onMar. 27, 2001, all of which are incorporated by reference in theirentirety.

BACKGROUND

This invention generally relates to devices for performing vascularanastomosis.

Vascular anastomosis, in which two vessels within a patient aresurgically joined together to form a continuous channel, are requiredfor a variety of conditions including coronary artery disease, diseasesof the great and peripheral vessels, organ transplantation, and trauma.For example, in coronary artery disease (CAD), an occlusion or stenosisin a coronary artery interferes with blood flow to the heart muscle. Inorder to restore adequate blood flow to the heart, a graft vessel in theform of a prosthesis or harvested artery or vein is used to rerouteblood flow around the occlusion. The treatment, known as coronary arterybypass grafting (CABG), can be highly traumatic to the patient's system.

In conventional CABG a large incision is made in the chest and thesternum is sawed in half to allow access to the heart. In addition,cardiopulmonary bypass, in which a patient's blood is circulated outsidethe body through a heart-lung machine, is used so that the heart can bestopped and the anastomosis performed. In order to minimize the traumato the patient's system induced by conventional CABG, less invasivetechniques have been developed in which the surgery is performed throughsmall incisions in the patient's chest with the aid of visualizingscopes. Less invasive CABG can be performed on a beating or anon-beating heart and thus may avoid the need for cardiopulmonarybypass.

In both conventional and less invasive CABG, the surgeon has to suturethe graft vessel in place between the coronary artery and a bloodsupplying vein or artery. The suturing procedure is a time consuming,difficult process requiring a high level of surgical skill. In order toperform the suturing procedure, the surgeon must have relativelyunobstructed access to the anastomotic site within the patient. As aresult, in less invasive approaches which provide only limited access tothe patient's vessels, some of the major coronary vessels cannot bereached adequately, which can result in incomplete revascularization anda resulting negative effect on patient survival. Moreover, certaintarget vessels, such as heavily calcified coronary vessels, vesselshaving a very small diameter of less than about 1 mm, and previouslybypassed vessels, may make the suturing process difficult or impossible,so that a sutured anastomosis is not possible.

Additionally, a common problem with CABG has been the formation ofthrombi and atherosclerotic lesions at and around the grafted artery,which can result in the reoccurrence of ischemia. Moreover, secondoperations necessitated by the reoccurrence of arterial occlusions aretechnically more difficult and risky due to the presence of the initialbypass. For example, surgeons have found it difficult to saw the sternumin half during the next operation without damaging the graft vesselsfrom the first bypass which are positioned behind the sternum.

Therefore, it would be a significant advance to provide a suturelessvascular anastomosis in which the graft vessels can be positioned on avariety of locations on target vessels having a variety of differentdiameters, which is easily performed, and which minimizes thrombosisassociated with the anastomosis. The present invention satisfies theseand other needs.

SUMMARY OF THE INVENTION

The invention is directed to anastomotic stents for connecting a graftvessel to a target vessel, and methods of use thereof. The anastomoticstents of the invention are suitable for use in a variety of anastomosisprocedures, including coronary artery bypass grafting. The term “targetvessel” refers to vessels within the patient which are connected toeither or both of the upstream and the downstream end of the graftvessel. One embodiment of the invention comprises a large vesselanastomotic stent for use with large diameter target vessels such as theaorta or its major side branches. Another embodiment of the inventioncomprises a small vessel anastomotic stent for use on a target vesselwhich has a small diameter such as a coronary artery. Another aspect ofthe invention involves applicators for use with the stents of theinvention. The terms “distal” and “proximal” as used herein refer topositions on the stents or applicators relative to the physician. Thus,the distal end of the stent is further from the physician than is thestent proximal end. The proximal end of an implanted stent is furtherfrom the center of the target vessel lumen than is the stent distal end.

The large vessel anastomotic stents of the invention generally comprisea substantially cylindrical body having a longitudinal axis, an openproximal end, an open distal end, a lumen therein, and at least onedeformable section which radially expands to form a flange. The stent,with one end of a graft vessel attached thereto, is inserted into anincision in a wall of the target vessel with the deformable section in afirst configuration, and the deformable section is radially expanded toa second configuration to deploy the flange. The flange applies an axialforce, substantially aligned with the stent longitudinal axis, againstthe wall of the target vessel. Additionally, the flange is configured toapply a radial force, substantially transverse to the stent longitudinalaxis, against the wall of the target vessel, to secure the stent to thetarget vessel.

In one embodiment of the large vessel stent, the stent has a singledeformable section forming a flange, preferably on a distal section ofthe stent. However, a plurality of deformable sections may be providedon the stent. For example, in an alternative embodiment, the stent has asecond deformable section on a proximal section of the stent. With theproximal and distal end flanges deployed, the stent is prevented fromshifting proximally out of the target vessel or distally further intothe interior of the target vessel.

The large vessel stents of the invention are configured to connect totarget vessels of various sizes having a wall thickness of at leastabout 0.5 mm, and typically about 0.5 mm to about 5 mm. In oneembodiment of the invention, the large vessel anastomotic stent isconfigured to longitudinally collapse as the deformable section isradially expanded. The surgeon can control the longitudinal collapse tothereby position the distal end flange at a desired location at leastpartially within the incision in the target vessel wall. Moreover, inthe embodiment having a proximal end flange, the surgeon can control theposition of the proximal end flange by longitudinally collapsing thestent to a greater or lesser degree, to thereby position the proximalend flange at a desired location in contact with the target vessel.Thus, regardless of the thickness of the target vessel wall, the stentcan be longitudinally collapsed to position the flanges against thetarget vessel wall and effectively connect the stent thereto. Thisfeature is significant because the stent must be connected to targetvessels which have a wide range of wall thickness. For example, theaortic wall thickness is typically about 1.4 mm to about 4.0 mm.Therefore, regardless of the thickness of the target vessel wall, thedegree of deployment of the proximal end flange, and thus thelongitudinal collapse of the stent, can be controlled by the physicianto thereby effectively connect the stent to the target vessel. Forexample, the surgeon may choose between partially deploying the proximalend flange so that it is positioned against an outer surface of thetarget vessel wall, or fully deploying the flange to position it incontact with the media of the target vessel wall within the incision inthe target vessel wall.

In a presently preferred embodiment, the graft vessel is attached to thestent before insertion into the patient by placing the graft vesselwithin the lumen of the stent, and everting the end of the graft vesselout the stent distal end and about at least the distal deformablesection. In a presently preferred embodiment, the graft vessel iseverted about at least the section which contacts the media of thetarget vessel wall proximal to the distal deformable section, tofacilitate sealing at the anastomosis site.

In a presently preferred embodiment of the invention, the deformablesection on the large vessel stent comprises a plurality of helicalmembers interconnected and disposed circumferentially around the stent.By rotating the distal end and the proximal end of the stent relative toone another, the helical members radially expand and the stentlongitudinally collapses to form the flange. In a presently preferredembodiment, the distal flange is configured to deploy before theproximal end flange.

Another aspect of the invention comprises the applicators designed forintroducing and securing the large vessel anastomotic stents of theinvention to the target vessel. One such applicator is configured toapply torque and axial compressive load to the large vessel stent, tothereby radially expand the deformable section which forms the flange.The applicator of the invention may be provided with a sharp distal end,to form an incision in the target vessel wall through which the stent isinserted or to otherwise facilitate insertion of the stent into thetarget vessel wall. Another embodiment of the applicator of theinvention includes a catheter member having one or more inflatablemembers designed to expand the incision in the target vessel andintroduce the large vessel stent therein.

Another embodiment of the invention comprises small vessel anastomoticstents for use on small target vessels such as coronary arteries. Thesmall vessel stents generally comprise an outer flange configured to bepositioned adjacent an outer surface of the target vessel, and an innerflange configured to be positioned against an inner surface of thetarget vessel and connected to the outer flange. The outer and innerflanges generally comprise a body defining an opening, with one end ofthe graft vessel secured to the outer flange.

The small vessel anastomotic stents of the invention are used on smalltarget vessels having a wall thickness of less than about 1.0 mm, andtypically about 0.1 mm to about 1 mm. For example, small target vesselsinclude coronary arteries. Despite the small size of the target vessels,the small vessel stents of the invention provide sutureless connectionwithout significantly occluding the small inner lumen of the targetvessel or impeding the blood flow therethrough.

In a presently preferred embodiment of the invention, the graft vesselis received into the opening in the outer flange and everted around thebody of the outer flange to connect to the outer flange. In anotherembodiment, as for example when the graft vessel is a mammary artery,the graft vessel is connected to the outer flange by connecting memberssuch as sutures, clips, hooks, and the like.

The outer flange, with the graft vessel connected thereto, is looselyconnected to the inner flange before insertion into the patient. Thespace between the loosely connected inner and outer flanges is at leastas great as the wall thickness of the target vessel so that the innerflange can be inserted through an incision in the target vessel and intothe target vessel lumen, with the outer flange outside the targetvessel. With the outer and inner flanges in place on either side of awall of the target vessel, tightening the flanges together compresses asurface of the graft vessel against the outer surface of the targetvessel. This configuration forms a continuous channel between the graftvessel and the target vessel, without the need to suture the graftvessel to the target vessel wall and preferably without the use of hooksor barbs which puncture the target vessel.

In one embodiment of the invention, the inner flange is introduced intothe target vessel in a folded configuration and thereafter unfolded intoan expanded configuration inside the target vessel. The foldedconfiguration reduces the size of the inner flange so that the size ofthe incision in the target vessel wall can be minimized. Folding theflange minimizes trauma to the target vessel and restenosis, andfacilitates sealing between the graft and target vessel at theanastomotic site.

In a presently preferred embodiment of the invention, the inner andouter flanges are connected together by prongs on one member configuredto extend through the body of the other member. However, the inner andouter flanges may be connected together by a variety of different typesof connecting members such as sutures, hooks, clips, and the like. In apresently preferred embodiment, the flange members are connectedtogether by prongs on the inner member configured to extend through theincision in the target vessel wall, without puncturing the wall of thetarget vessel, and through prong receiving openings in the body of theouter flange. The prong receiving openings in the outer flange may beconfigured to allow for the forward movement of the prong through theopening to bring the inner and outer flanges together, but prevent thebackward movement of the prong out of the opening, so that the inner andouter flanges remain substantially compressed together to seal theanastomotic site.

Another aspect of the invention comprises a small vessel stentapplicator which facilitates introduction of the inner flange into thetarget vessel lumen, and connection of the inner flange to the outerflange around the target vessel. In one embodiment of the small vesselstent applicator, the applicator folds the inner flange into the foldedconfiguration for introduction into the lumen of the target vessel.

Anastomotic systems of the invention may comprise combinations of thelarge and small vessel stents of the invention, for connecting one orboth ends of a graft vessel to target vessels. Typically, in a coronarybypass using the anastomotic system of the invention, a large vesselstent connects the proximal end of the graft vessel to the aorta, and asmall vessel stent connects the distal end of the graft vessel to anoccluded coronary artery. However, it will be apparent to one ofordinary skill in the art that various combinations and uses of theanastomotic stents of the invention may be used. For example, inpatients with an extreme arteriosclerotic lesion in the aorta, which mayresult in serious complications during surgical procedures on the aorta,the anastomotic stents of the invention allow the surgeon to avoid thisregion and connect the proximal end of the graft vessel to any otheradjacent less diseased vessel, such as the arteries leading to the armsor head.

The large and small vessel stents of the invention are provided in arange of sizes for use on various sized graft vessels. Thus, theanastomotic stents of the invention can be used with venous grafts, suchas a harvested saphenous vein graft, arterial grafts, such as adissected mammary artery, or a synthetic prosthesis, as required.

Connection of the large vessel stent does not require the stoppage ofblood flow in the target vessel. Moreover, the anastornotic stents ofthe invention can be connected to the target vessel without the use ofcardiopulmonary bypass. Additionally, the surgeon does not needsignificant room inside the patient to connect the anastomotic stents ofthe invention to the target vessel. For, example, unlike suturedanastomoses which require significant access to the aorta for thesurgeon to suture the graft vessel thereto, the anastomotic stents ofthe invention allow the proximal end of the graft vessel to be connectedto any part of the aorta. All parts of the aorta are accessible to thelarge vessel stents of the invention, even when minimally invasiveprocedures are used. Consequently, the graft vessel may be connected tothe descending aorta, so that the graft vessel would not be threatenedby damage during a conventional sternotomy if a second operation isrequired at a later time.

The anastomotic stents of the invention provide a sutureless connectionbetween a graft and a target vessel, while minimizing thrombosis orrestenosis associated with the anastomosis. The anastomotic stents canbe attached to the target vessel inside a patient remotely from outsidethe patient using specially designed applicators, so that the stents areparticularly suitable for use in minimally invasive surgical procedureswhere access to the anastomosis site is limited. The stents of theinvention allow the anastomosis to be performed very rapidly, with highreproducibility and reliability, and with or without the use ofcardiopulmonary bypass.

These and other advantages of the invention will become more apparentfrom the following detailed description of the invention and theaccompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view, partially in phantom and in section, of asmall vessel stent of the invention, with a graft vessel, partially insection and broken away, connected thereto, positioned in a targetvessel.

FIG. 2 is a transverse cross sectional view of the small vessel stent,together with the graft and target vessel, shown in FIG. 1, taken alonglines 2—2.

FIG. 3 is an exploded view of the graft vessel, the small vessel stentwith the inner and outer flanges, and the graft vessel disconnected.

FIG. 4 is an elevational view, partially in phantom, of the small vesselstent shown in FIG. 3, with the outer flange and the graft vessel,partially broken away, connected thereto, and with the inner flange inthe target vessel lumen.

FIG. 5 is an elevational view of the small vessel stent shown in FIG. 4,connected to the target vessel.

FIG. 6 is an elevational view of a prong and a prong receiving opening,on the outer flange which embodies features of the invention.

FIG. 7 is an elevational view, partially in section, of a small vesselstent with the inner flange folded for insertion into the target vessel,with the short dimension sides folded inward, and with the graft vessel,partially broken away.

FIG. 8 is an elevational view, partially in section, of a small vesselstent with the inner flange folded for insertion into the target vessel,with the short dimension sides and the long dimension sides foldedinward, and with the graft vessel, partially broken away.

FIG. 9 is an elevational view of an compressible small vessel stentinner flange in a partially compressed configuration.

FIG. 10 is an elevational view, partially in section, of a small vesselstent applicator which embodies features of the invention.

FIG. 11 is a longitudinal cross sectional view of the applicator shownin FIG. 10 with a small vessel stent therein, in position in a targetvessel.

FIG. 12 is an elevational, exploded view of a graft vessel, a largevessel anastomotic stent of the invention with the deformable sectionsin the first configuration, and a target vessel.

FIG. 13 is a transverse cross sectional view of the large vessel stentshown in FIG. 12, taken along lines 13—13.

FIG. 14 is an flattened view of a large vessel anastomotic stent of theinvention with the deformable sections in the first configuration.

FIG. 15 is an elevational view of a large vessel anastomotic stent ofthe invention with the distal deformable section in the secondconfiguration.

FIG. 16 is a transverse cross sectional view of the large vessel stentshown in FIG. 15, taken along lines 16—16.

FIG. 17 is an elevational view, partially in section and broken away, ofthe large vessel stent shown in FIG. 12, with an everted graft vesselthereon, and a target vessel.

FIG. 18 is a longitudinal cross-sectional view of the large vessel stentand graft vessel thereon in a target vessel.

FIG. 19 is a longitudinal cross-sectional view of the large vessel stentshown in FIG. 18, with the distal end deformable section in the secondconfiguration.

FIG. 20 is a longitudinal cross-sectional view of the large vessel stentshown in FIG. 19, with the proximal end deformable section in the secondconfiguration.

FIG. 21 is a flattened view of an alternative embodiment of the largevessel anastomotic stent of the invention having voids in the body.

FIG. 22 is a flattened view of an alternative embodiment of the largevessel anastomotic stent of the invention having a curvilinear distalend.

FIG. 23 is an elevational view of a large vessel stent applicator whichembodies features of the invention.

FIG. 24 is a transverse cross sectional view, partially in section andbroken away of the distal end of an applicator with a large vessel stentand graft vessel thereon, with a vessel penetrating member therein.

FIGS. 25 and 26 are transverse cross sectional views of the applicatorassembly shown in FIG. 24 taken along lines 25—25 and 26—26,respectively.

FIG. 27 is an elevational view of the distal end of the applicator shownin FIG. 23.

FIGS. 28A–28H are elevational views, partially in section, of theapplicator, and large vessel stent and vessel penetrating member thereinduring connection of the large vessel stent to a target vessel.

FIG. 29 is an transverse cross sectional view of an alternativeembodiment of the large vessel stent having a distal flange angledtoward the distal end of the stent.

FIG. 30 is an elevational view of a human heart having a graft vesselattached thereto.

DETAILED DESCRIPTION OF THE INVENTION

A presently preferred embodiment of the small vessel stent 10 of theinvention, for connecting one end of a graft vessel to a small targetvessel, is illustrated in FIG. 1. The small vessel stent 10 comprises anouter flange 11 having a body 12 which defines an opening 13 configuredto receive the end of the graft vessel 21, and an inner flange 14 havinga body 15 which defines an opening 16. The inner flange is configured tobe connected to the outer flange, with the openings 13, 16 at least inpart aligned. In the embodiment illustrated in FIG. 1, prongs 17 on theinner flange are configured to be received within small openings 18 inthe outer flange, to thereby connect the flanges together. As bestillustrated in FIG. 2, showing a transverse cross section of the smallvessel stent 10 shown in FIG. 1, taken along lines 2—2, the inner flange14 is configured to be positioned within a lumen 23 of the target vessel22 against an inner surface 24 of the target vessel, and the outerflange 11 is configured to be positioned against an outer surface 25 ofthe target vessel 22. In the embodiment illustrated in FIGS. 1 and 2,the inner and outer flanges have an arced configuration to facilitatepositioning against the arced surface of the tubular vessel. The smallvessel stent 10 is preferably used with small target vessels, such asarteries, which typically have thin walls and small inner diameters.

In the embodiment illustrated in FIG. 1, the inner and outer flangeshave a short dimension and a long dimension, i.e. are substantiallyoblong. The graft receiving opening 13 in the outer flange, and theopening 16 in the inner flange, are also substantially oblong.

FIG. 3 is an exploded view of the inner flange 14, outer flange 11, anda graft vessel 21, at an incision 26 in the target vessel 22. In FIG. 4,the graft vessel has been connected to the outer flange by inserting theend of the graft vessel through the graft receiving opening 13, andeverting the graft end over the outer flange. Additionally, connectingmembers such as sutures, hooks or clips may be used to fix the graftvessel to the outer tubular member (not shown). The prongs 17 on theinner flange pierce through the wall of the graft vessel and thenthrough the small openings 18 in the outer flange. FIG. 4 illustratesthe inner and outer flanges loosely connected together for positioningat the target vessel, with only a partial length of the prongs 17inserted through the prong receiving opening 18, before the flanges aretightened down around the wall of the target vessel.

With the outer flange 11 connected to the graft vessel 21 and the innerflange 14 connected to the outer flange 11, the inner flange isintroduced into the incision 26 in the target vessel 22, and the innerand outer flanges are tightened together so that a compressive force isapplied to the graft vessel against the outer surface 25 of the targetvessel. Thus, the anastomosis channel is formed from the target vessellumen, through opening in the inner flange, and into the graft vessellumen. After the inner and outer flanges are tightened around the wallof the target vessel, in the embodiment having prongs 17, a length ofthe prongs extending above the target vessel can be broken off orotherwise removed. FIG. 5 is an elevational view of the small vesselstent shown in FIG. 4, connected to the target vessel, with a length ofthe free ends of the prongs 17 removed.

In one embodiment of the invention, the prongs 17 on the inner flangeand the prong receiving openings 18 on the outer flange are configuredto fixedly mate together. FIG. 6 illustrates one embodiment of the prong17 and prong receiving openings 18. The opening 18 has deflectable tabs19 which deflect to allow displacement of the prong 17 longitudinallyinto the opening from the under side of the outer flange to the upperside of the outer flange, but which wedge against the prong to preventthe inserted prong from moving out of the opening 18 from the upper sideto the under side of the outer flange. Additionally, a quick release(not shown) may be provided on the prongs to allow the prongs which areonly partially inserted through the prong receiving opening to bequickly released therefrom in the event of an aborted procedure.

In a presently preferred embodiment of the small vessel stent, the innerflange has a folded configuration having a reduced profile to facilitateinsertion into the incision in the target vessel. In one embodiment, thelength of the stent is shortened by flexing the short dimensioned sidesof the stent together, as illustrated in FIG. 7. To hold the innerflange in the folded configuration for insertion into the target vessel,a pair of inwardly tensioned arms 43, preferably as a part of anapplicator, are used in one embodiment of the invention. Additionally,the width of the stent can be shortened by flexing the long dimensionedsides of the stent together, as illustrated in FIG. 8. In the presentlypreferred embodiment of the folding inner flange illustrated in FIGS. 7and 8, the inner flange is formed from a superelastic or pseudoelasticmaterial, such as a NiTi alloy, to facilitate folding the inner flangeand to provide improved sealing against the wall of the target vesselafter the inner flange is unfolded inside the target vessel lumen.However, other configurations may be used, as for example, an innerflange having a collapsible section. For example, FIG. 9 illustrates aninner flange having a collapsible section 27 on the long dimensionedsides of the inner flange, comprising a series of short turns inalternating directions. In FIG. 9, the collapsible section 27 is shownin a partially collapsed configuration in which the length of the innerflange is shortened by collapsing the long dimensioned sides of theinner flange. In a presently preferred embodiment, the inner flangehaving a collapsible section 27 is formed of stainless steel.

FIG. 10 illustrates an applicator 31 used to position the inner flange14 within the target vessel lumen 23, and tighten the inner and outerflanges together around the wall of the target vessel. The applicator 31generally comprises a shaft 32 with proximal and distal ends, a handle33 on the proximal end, and a connecting member 34 on the distal end forreleasably attaching to the small vessel stent. In the embodimentillustrated in FIG. 9, the connecting member 34 comprises an innercompressible member 35 which is slidably insertable into an outerhousing member 36. The compressible member 35 has slots 37 configured toreceive the prongs 17 on the inner flange 14, and an opening 38configured to receive the graft vessel. The free end of the graftvessel, unconnected to the small vessel stent 10, is outside of theapplicator via the opening 38. The housing member 36 has an innerchamber 39 configured to receive the compressible member 35. The chamber39 is smaller than at least a section of the compressible member 35, tothereby compress the compressible member 35 to a smaller dimension whenit is positioned within the chamber 39. The small vessel stent isreleasably connected to the applicator, after the inner and outer flangetogether with a graft vessel are connected together, by inserting theprongs 17 on the inner flange into the slots 37. The compressible member35 clamps onto the prongs 17 as the compressible member 35 is positionedwithin the chamber 39 and the slots 37 are thereby compressed. In theembodiment illustrated in FIG. 10, the compressible member 35 ispartially out of the housing. Additionally, a connecting member (notshown) such as a clasp, clamp, or hook on the distal end of theapplicator may be used to connect the outer flange to the applicator.FIG. 10 illustrates, in an exploded view, the positioning of the innerflange 14 for releasably connecting to the applicator. Of course, asdiscussed above, the inner flange 14 is typically connected to the outerflange with a graft vessel attached thereto before being connected tothe applicator. The applicator is then used to position the stent inplace at the incision in the target vessel, with the inner flange insidethe target vessel lumen and the outer flange against the outer surfaceof the target vessel. To release the small vessel stent 10 from theapplicator, the compressible member 35 is displaced out of the housingmember 36, so that the prongs 17 are released from the slots 37 as theslots expand. In the embodiment illustrated in FIG. 10, the applicatorhas a knob 41 for turning the shaft 32 to draw the compressible member35 up into the chamber 39. The handle 33, may be used to deploy thesmall vessel stent by squeezing the handle together to displace thecompressible member 35 and housing member 36 relative to one another.FIG. 11 is a longitudinal cross sectional view of an applicator as shownin FIG. 10, with a small vessel stent therein, in position at a targetvessel.

In addition, the applicator 31 may be provided with a insertion memberfor holding the inner flange in the folded configuration facilitatingintroduction into the target vessel lumen through the incision in thetarget vessel. In one embodiment, the applicator insertion membercomprises a pair of inwardly tensioned arms 43 extending past the distalend of the shaft for releasably holding the inner flange in the foldedconfiguration, as illustrated in FIGS. 7 and 8.

In the method of the invention, the small vessel stent connects one endof a graft vessel to a target vessel to form an anastomosis. The targetvessel is incised, and balloons on occlusion catheters positionedagainst the target vessel are inflated to occlude blood flow upstreamand downstream of the anastomosis site. The outer flange is attached toone end of a graft vessel as described above, and, in the embodimentillustrated in FIG. 1, the prongs on the inner flange are insertedthrough the graft vessel and into the prong receiving openings in theouter flange. The graft vessel may be occluded with a temporary clamp onthe mid portion of the graft, to prevent blood loss through the graftvessel during the procedure. The inner flange is inserted into thetarget vessel lumen, and the inner and outer flanges are tightenedtogether to compress the graft vessel against the outer surface of thetarget vessel. After the inner and outer flanges are tightened together,the free end of each prong is broken off to decrease the length of theprongs left inside the patient. The prongs are typically provided with aweakened point 42 near the body of the inner flange to facilitatebreaking of the prong by tensile forces or by fatigue failure due tostrain hardening. The occlusion balloons are deflated and the occlusioncatheters removed, with the stent connected to the target vessel and thegraft vessel in fluid communication with the target vessel lumen.

In the embodiment illustrated in FIG. 1, the outer flange is longer andwider than the inner flange. The outer flange has a length of about 4 mmto about 12 mm, preferably about 7 mm to about 9 mm, and a width ofabout 1 mm to about 5 mm. The wall thickness of the body of the outerflange is about 0.10 mm to about 0.30 mm. The inner flange has a lengthof about 4 mm to about 12 mm, preferably about 7 mm to about 9 mm, and awidth of about 0.5 mm to about 5 mm, and preferably about 2 mm to about4 mm. The wall thickness of the body of the inner flange is about 0.10mm to about 0.25 mm. The inner and outer flanges are preferably formedof stainless steel, preferably 316 stainless steel, although, aspreviously discussed herein, superelastic or pseudoelastic materialssuch as nickel titanium alloys, titanium, or tantalum, may also be used.Additionally, advanced polymers which can be plastically deformed, suchas polyetheretherketone, may be used.

FIG. 12 illustrates a presently preferred embodiment of the large vesselstent 110 of the invention, for connecting one end of a graft vessel 125to a large target vessel 127. The large vessel stent 110 comprises asubstantially cylindrical body 111 having an open proximal end 112, opendistal end 113, a lumen 114 extending therein configured to receive theend of the graft vessel 125. FIG. 13 illustrates a transverse crosssection of the large vessel stent 110 shown in FIG. 12, taken alonglines 13—13. FIG. 14 illustrates a flattened view of the large vesselstent 110 shown in FIG. 12.

The cylindrical body has a distal deformable section 115 and a proximaldeformable section 116. The deformable sections 115, 116 have a firstconfiguration for insertion into the target vessel, and a radiallyexpanded second configuration for connecting to the target vessel. Inthe embodiment illustrated in FIG. 12, the distal and proximaldeformable sections 115, 116 comprises a plurality of helical members123, 124, respectively. In the embodiment illustrated in FIG. 12, eachhelical member has a proximal end radially spaced on the stent bodyrelative to the helical member distal end. The helical members areradially spaced around the circumference of the cylindrical body betweenlongitudinally spaced portions of the cylindrical body. In FIG. 12, thehelical members forming the deformable sections are shown in the firstconfiguration prior to being radially expanded to the secondconfiguration. As illustrated in FIG. 15, the distal deformable section115 radially expands to the second configuration to form a distal endflange 121, configured to apply a force radial to the cylindrical body111 longitudinal axis against the target vessel and thereby connect thestent to the target vessel. Similarly, the proximal deformable section116 radially expands to the second configuration to form a proximal endflange 122, as illustrated in FIG. 20. The flanges 121, 122 are deployedby circumferentially rotating the proximal end of the stent bodyrelative to the distal end of the stent body. Such rotation causes thestent body to longitudinally collapse as the helical members radiallyexpand from the first to the second configuration. FIG. 16 illustrates atransverse cross section of the large vessel stent 110 shown in FIG. 15,taken along lines 16—16.

FIG. 17 illustrates the large vessel stent shown in FIG. 12 with a graftvessel 125 attached thereto. The graft vessel is attached to the largevessel anastomotic stent by inserting one end of the graft vessel intothe proximal end of the cylindrical body and, in a preferred embodiment,everting the graft end 126 out the cylindrical body distal end. Thegraft vessel may be everted over all or only a section of the outersurface of the large vessel stent 110. In the embodiment illustrated inFIG. 17, the graft is everted over the distal deformable section 115which is in the first configuration prior to being radially expanded tothe second configuration.

FIGS. 18–20 illustrate the large vessel stent shown in FIG. 17 within awall of the target vessel 127 before and after deployment of the distalflange 121 and proximal flange 122. In FIG. 18, the stent has beeninserted into an incision in a wall of the target vessel, with thedistal end of the stent within the lumen 128 of the target vessel 127and the proximal end 112 of the stent extending outside of the targetvessel. In FIG. 19, the distal deformable section 115 has been radiallyexpanded to form the distal end flange 121. During deployment of thedistal end flange, the stent body longitudinally collapses, and thedistal end flange is positioned at least in part within the wall of thetarget vessel, so that the flange applies a force radial to the stentlongitudinal axis, illustrated by the arrow R, against the wall of thetarget vessel defining the incision therein. Additionally, an axialforce, illustrated by the arrow A, is applied against the target vesselwall, compressing the target vessel wall. The final position of thedistal end flange may vary, with the distal end flange being completelywithin the target vessel wall as shown, or, alternatively, partiallywithin the target vessel lumen (not shown). In FIG. 20, the proximaldeformable section 116 has been radially expanded to form the proximalend flange 122. The proximal end flange positioned against the outerwall of the target vessel produces an axial force, illustrated by thearrow A, against the target vessel. In the embodiment illustrated inFIG. 20, the proximal end flange is in contact with an outer surface ofthe target vessel wall. Alternatively, the proximal end flange may be incontact with the media of the target vessel between the inner and outersurface of the target vessel wall, and preferably with the proximal endof the stent flush with the outer surface of the target vessel (notshown). The degree to which flange is deployed may be varied to controlhow and where the flange contacts the target vessel wall. Thus,depending on the thickness of the target vessel wall, the proximaldeformable section can be radially expanded and longitudinally collapsedto a greater or lesser degree, so that the proximal end flange is incontact with the target vessel either on an outer surface of the targetvessel or within the incision therein in contact with the media of thetarget vessel wall.

Although the large vessel stent 110 is shown in FIG. 12 with a proximaldeformable section and a distal deformable section, forming proximal anddistal flanges, respectively, the large vessel stent may have one ormore deformable sections. For example, an intermediate deformablesection (not shown) between the proximal and distal end deformablesections may be provided for additional sealing and securing forceagainst the media of the target vessel wall.

In the large vessel stent illustrated in FIG. 12, the intermediatesection of the body is solid. FIG. 21 illustrates an alternativeembodiment in which voids or openings 129 are provided in the body wallwhich allow for tissue ingrowth, to thus facilitate sealing and securingof the anastomosis. In another embodiment of the large vessel stent,illustrated in FIG. 22, a peripheral edge on the distal end of the largevessel stent is curvilinear, so that deployment of the distal end flangeincreases the diameter of the open distal end. The generally sinusodialedge increases the diameter of the opening in the distal end as thedistal deformable section 115 is longitudinally collapsed.

An applicator 131 is typically used to deploy the flanges and connectthe large vessel stent 110 to the target vessel 127, as illustrated inFIG. 23. In the embodiment illustrated in FIG. 23, the applicator 131comprises an elongated stent delivery member comprising a shaft 133having an outer tubular member 134 having a lumen 135 therein, an innertubular member 136 having a lumen 137 configured to receive the graftvessel 125 and being rotatably located within the lumen of the outertubular member, a handle 138 on the proximal end of the shaft, andconnecting members 141 on the distal end of the inner and outer tubularmembers which releasably secure the large vessel stent 110 to theapplicator 131. The distal and proximal ends of the large vessel stent110 releasably secure to the inner and outer tubular members,respectively, and the inner and outer tubular members are rotatablerelative to one another, so that the distal end of the stent can berotated relative to the proximal end of the stent and the flangesthereby deployed. In the embodiment illustrated in FIG. 23, longitudinalopenings 139, preferably coextensive with one another, in the inner andouter tubular members are provided to facilitate positioning the graftvessel, and large vessel stent connected thereto, on the applicator 131.FIG. 24 illustrates an enlarged view of the distal end of an applicatoras shown in FIG. 23, with a large vessel stent 110 and graft vessel 125thereon. FIGS. 26 and 27 illustrate transverse cross sections of theapplicator shown in FIG. 24, taken along lines 26—26 and 27—27,respectively.

FIG. 27 illustrates an enlarged view of the distal end of the applicator131 shown in FIG. 23. In the embodiment illustrated in FIG. 27, theconnecting members 141 on the outer tubular member 134 comprise tabs 142configured to mate with slits 143, as illustrated in FIG. 12, on theproximal end of the stent. The connecting members 141 on the innertubular member 136 comprise angular slits 144 which slidably receivetabs 145, as illustrated in FIG. 13 on the distal end of the stent. Thetabs on the distal end of the stent are introduced into the slits on theapplicator inner tubular member and a slight twisting motion releasablysecures the tabs therein. A variety of suitable connection members canbe used including releasable clamps, clips, hooks, and the like.

In one embodiment of the invention, the applicator 131 includes a vesselpenetrating member 146, as illustrated in FIGS. 24 and 28, for formingan incision in the target vessel. Additionally, the applicator may beprovided with one or more inflatable members for enlarging the incision,and/or drawing the applicator and stent into the incision. For example,in the embodiment shown in FIG. 28, a vessel penetrating member 146having proximal and distal ends, a piercing member 147 on the distalend, and at least one inflatable member on a distal section of member146, is configured to be received in the inner lumen of the innertubular member 136; In the presently preferred embodiment illustrated inFIG. 28, a proximal balloon 148, which is preferably formed fromnoncompliant material, is provided on the outer tubular member forexpanding the incision in the target vessel, and a distal balloon 151,which is preferably formed from compliant material, is provided distalto the noncompliant balloon 148, for drawing the vessel penetratingmember 146 into the target vessel lumen 128. However, the distal balloonmay be omitted and the catheter advanced through the incision and intothe target vessel lumen physically or by other suitable methods, as whenthe proximal balloon is shaped to advance into the target vessel lumenduring inflation. Additionally, the target vessel may be held to resistthe force of inserting the stent into the aortal wall, as by a suctionapplicator (not shown) positioned against an outer surface of the targetvessel, which pulls the target vessel toward the applicator.

In the method of the invention, the large vessel stent, with a graftvessel connected thereto, is introduced into the patient, inserted intothe target vessel and connected thereto by deployment of the flange.FIGS. 28A–28H illustrate the connection of the large vessel stent to atarget vessel. The stent 110, with an everted graft vessel 125 thereon,is releasably secured to the distal end of the applicator. The graftvessel is within the lumen of the inner tubular member, and the vesselpenetrating member 146 is within the lumen of the graft vessel 125. Asshown in FIG. 28A, the applicator 131 and stent 110 assembly isintroduced into the patient and positioned adjacent the target vessel127. An incision in the target vessel wall is formed by inserting thepiercing member 147 into the target vessel, and the incision is enlargedby inflating the proximal balloon 148 on the vessel penetrating member146, see FIGS. 28B and 28C. The distal end of the applicator is thendisplaced distally into the target vessel lumen 128 by inflating thedistal balloon 151, see FIG. 28D. With the stent in position within theincision in the target vessel, the applicator inner tubular member isrotated relative to the applicator outer tubular member, so that thedistal end of the stent rotates relative to the proximal end of thestent, and the distal end flange is deployed, see FIG. 28E. In theembodiment illustrated in FIG. 28D, the distal end of the stent ispositioned within the target vessel lumen before the distal end flange121 is deployed, to facilitate deployment thereof. In a presentlypreferred embodiment, the distal deformable section is positioned atleast in part within the target vessel lumen before the distal flange isdeployed. However, it is not required that the deformable sections areoutside of the incision in the target vessel wall for the flanges to bedeployed. The proximal end flange 122 is deployed by further rotatingthe applicator tubular members as outlined above for the distal endflange, see FIG. 28F. The balloons 148, 151 on the vessel penetratingmember 146 are then deflated and the applicator 131 removed from thetarget vessel 127, leaving the graft vessel 125 connected thereto, seeFIGS. 28G and 28H.

In a presently preferred embodiment, the distal end flange is configuredto deploy at lower torque than the proximal end flange. A deflectingsection 153 is provided on the helical members 123, 124, which bendsduring the deployment of the flanges. In one embodiment of theinvention, illustrated in FIG. 14, the deflecting section 153 is formedby at least one notch in each helical member, having a depth whichdecreases the transverse dimension of the helical members at the notch.In the embodiment of the large vessel stent illustrated in FIG. 14, thea deflecting section is formed by two opposed notches 154 on oppositesides of the helical members. The notches on the distal helical membershave a depth that is greater than the depth of the notches on theproximal helical members. Consequently, the transverse dimension of thedeflecting section on the distal helical member is smaller than that ofthe proximal helical members, so that the distal flange will deploybefore the proximal flange. Thus, the distal section helical membersradially expand at lower torque than the proximal helical members, sothat rotating the proximal and distal ends of the stent body relative toone another causes the distal end flange to deploy first, followed bythe proximal end flange.

In the embodiment illustrated in FIG. 14, the helical members havedeflecting sections 153 on the proximal and distal ends, and anintermediate deflecting section located substantially centrally alongthe length of the helical member between the proximal and distal ends ofthe helical member. In the deployed flange, the intermediate deflectingsection is thus located on a peripheral extremity of the deployed flangeand the flange is substantially perpendicular to the stent longitudinalaxis. Alternatively, the intermediate deflecting section may be locateddistally or proximally along the length of the helical member, so thatthe flange is angled relative to the longitudinal axis of the stent. Forexample, where the intermediate deflecting section is located betweenthe center point and the distal end of the helical member, the flange isangled toward the distal end of the large vessel stent 110, asillustrated in FIG. 29.

In the embodiment of the large vessel stent illustrated in FIGS. 18–20,the length of the large vessel stent before deployment of the flanges isgreater than the width of the target vessel wall, so that the deformablesections are on either side of the target vessel, at least in partoutside of the incision in the target vessel wall. The length of thestent after the flanges are deployed, as illustrated in FIG. 20, issubstantially equal to the width of the target vessel wall. The lengthof the stent 110 is about 0.5 mm to about 5 mm, and the diameter isabout 4 mm to about 10 mm. The large vessel stent is preferably formedfrom stainless steel. However, other suitable materials may be used,including tantalum, titanium, and alloys thereof. The large vessel stentwall thickness is about 0.10 mm to about 0.20 mm.

The anastomotic stents of the invention may be used for a variety ofanastomosis procedures, including coronary bypass surgery. For example,the distal end of a dissected mammary artery can be connected to acoronary artery, using a small vessel stent of the invention. Typically,one or more slices are made in the end of the mammary artery in order toincrease to diameter of the mammary artery to facilitate its connectionto the outer flange of the small vessel stent. FIG. 30 illustrates aheart 160 on which a coronary bypass has been performed using theanastomotic stents of the invention. The distal end of a harvested veingraft 125 is connected to the coronary artery 161 using a small vesselstent of the invention, and the proximal end of the graft vessel isconnected to the descending aorta 162 using a large vessel stent of theinvention.

In an anastomotic system using the large vessel stent in combinationwith the small vessel stent, the large vessel stent would preferably beconnected to the target vessel first, so that the lumen of the graftvessel would be accessible through the other end of the graft vessel, tothereby provide access for a catheter which incises and expands theaortal wall. The small vessel stent would be connected next, because itrequires no access through the lumen of the graft vessel.

Although principally discussed with respect to coronary bypass surgery,the anastomotic stents of the invention may be used in a number ofanastomosis procedures. For example, the other types of anastomosisprocedures include, femoral-femoral bypass, vascular shunts,subclavian-carotid bypass, organ transplants, and the like.

It will be apparent from the foregoing that, while particular forms ofthe invention have been illustrated and described, various modificationscan be made without departing from the spirit and scope of theinvention. For example, those skilled in the art will recognize that thelarge and small vessel stents of the invention may be formed of wound orbended wire, filaments and the like. Other modifications may be madewithout departing from the scope of the invention.

1. Apparatus, comprising: an anastomosis device including at least onecurved prong and at least one second element; wherein at least one saidcurved prong is frangible; wherein at least one said curved prong isconnectible to at least one said second element; and wherein at leastone said second element includes at least one opening therethrough andat least one deflectable tab extending into said opening, wherein onesaid curved prong is receivable into each said opening and engageable byat least one said tab.
 2. The apparatus of claim 1, wherein saidanastomosis device includes a single second element.
 3. The apparatus ofclaim 2, wherein said second element is substantially annular.
 4. Theapparatus of claim 1, wherein at least one said second element iscomposed of superelastic material.
 5. The apparatus of claim 4, whereinsaid superelastic material is nickel-titanium alloy.
 6. Apparatus,comprising: an anastomosis device comprising at least one inner elementhaving a frangible curved prong connected thereto and at least one outerelement spaced longitudinally apart from at least one said inner elementand connectable to at least one said inner element by at least one saidfrangible curved prong; wherein at least one said outer element includesat least one opening therethrough and at least one deflectable tabextending into said opening, wherein a curved prong is receivable intoeach said opening and engageable by at least one said tab.
 7. Theapparatus of claim 6, wherein said anastomosis device includes a singieouter element.
 8. The apparatus of claim 7, wherein said outer elementis substantially annular.
 9. The apparatus of claim 6, wherein at leastone said outer element is composed of superelastic material.
 10. Theapparatus of claim 9, wherein said superelastic material isnickel-titanium alloy.